Insulation panel and fastener assembly and method



M rch 12, 1968 w. M. CHARMANi JR. ET'AL 3,372,524

INSULATION PANEL AND FASTENER ASSEMBLY AND METHOD Filed on. 31, 1966 'IIIIIIIIIII I WALTER M. (WAN JR. JOHN E UGENE JAL'KSON AT PNEY" United States Patent 3,372,524 INSULATHON PANEL AND FASTENER ASSEMBLY AND METHOD Walter M. Charman, Jr., Shaker Heights, and John Eugene Jackson, Beechwood, Ohio, assignors to Oglebay Norton Company, Cleveland, Ohio, a cor poration of Delaware Filed Oct. 31, 1966, Ser. No. 590,808 1 Claim. (Cl. 52-747) This invention relates to a method of installing a heat insulation panel in an ingot mold, to a pre-assembled insulation panel and fastener assembly for such use, and to improvements in the fastener itself.

It has been the practice for some time to attach heat insulation panels at the inside of the upper end of an iron ingot mold to provide a heat insulating liner or hot top for the purpose of maintaining a reservoir of hot metal on top of the ingot during solidification, as is well known in the art. Such insulation panels must be so firmly attached to the ingot mold that they are maintained in proper position during movement of the mold, usually by rail, from the location where the heat insulation panels are installed to the pouring pit. During the pouring operation, the heat insulation panels must not loosen and fioat out of their position against the mold wall, which they tend to do because of the great difference in specific gravity between the panels and the molten steel. Such floating out of a panel destroys its function as a hot top and usually results in a piped ingot and loss of yield. It is also important to prevent any appreciable amount of steel from rising up and solidifying between the heat insulation panels and the mold walls during the pouring operation. Such steel fins between the panels and mold walls may tend to prevent the escape of any gases generated by the burning of any organic materials or binders in the panels, causing boiling and displacement of the panels during pouring. Such fins also cause difliculties during the later rolling of the ingot, by folding back and rolling into and marking the surface of the good product in the ingot.

Prior to the present invention, the heat insulation panels have been attached to ingot mold walls by using a fastening tool to drive steel fastening pins through the panel and into the iron mold wall. In accordance with this practice, the fastening tool is a gun-like, explosive powder-actuated, impact tool having a recess in its muzzle end into which the user may insert by hand a fastener pin with a washer thereon. The barrel of the tool contains a slidable piston for driving the fastener pin through the heat insulation panel and into the mold wall. A powder charge cap in the tool is exploded, by means of a spring-actuated firing pin, and such explosion drives the piston forward in the barrel to force the fastener pin through the heat insulation panel and into the mold wall. With one type of tool commonly used, a mechanical blow on a plunger, which in turn strikes and explodes the powder charge, is provided by a hammer which is swung by the operator. This requires that there be enough clearance across the inside of the ingot mold for the operator to do this conveniently. Also, it requires a firm backup for the heat insulation panel so that, when the impact blow is struck with the hammer, the energy of the blow is not cushioned by movement of the panel toward the mold wall. If this occurs, the explosive charge cap may not fire. Also, sometimes the hammer blow may break the heat insulation panel, or if the panel is not held firmly against the mold wall the fastener pin and its washer may be driven too far into the panel and may produce a hole in the panel the diameter of the washer, with consequent loss of bolding force of the panel against the mold wall.

Safety is another problem with this prior practice.

3,372,524 Patented Mar. l2, 1968 Since the fastener pin must be inserted manually into the impact gun before the latter is positioned down inside the mold for use, there is a possibility that the impact gun can be fired accidentally before it is so positioned. As a safety precaution, in the prior practice the impact gun is provided with a safety nose on its muzzle end which prevents the gun from being fired until the nose is retracted by forcing it against the panel in place at the inside of the ingot mold. Since considerable force must be exerted to retract this safety nose, this is usually an awkward operation because the workman must perform it while leaning down from the top of the ingot mold. Powder-actuated impact guns require a licensed operator in some states for safety reasons, and this limits their use for the purpose intended.

Another disadvantage of the prior practice is that the work is usually done with the operator standing on top of the ingot mold, and he must drive the fastener pins into the heat insulation panel which is below the top of the mold on which he is standing. This practice is slow and laborious, since ten or more fastener pins must be driven on the larger mold sizes, and each shot requires that the breech of the impact gun be opened, a new powder cap installed, a fastener pin and washer installed and held in the barrel of the gun, the gun held against the panel, and the gun be discharged by striking a hammer blow. Before shooting starts, mold clips or clamps usually must be installed to hold the panels against the mold wall.

The present invention is directed to improving the safety and the ease and speed with which such heat insulation panels can be installed in an ingot mold.

In accordance with the present invention, the heat insulation panel and as many fastener pins as are needed for it are pre-assembled as a unitary structure, with the fastener pins preset to a predetermined depth in the panel and having their head ends projecting from one side of the panel. The pre-setting of the fastener pins in the panel eliminates the need for their insertion by the operator manually into the fastening g un. Instead, the operator simply telescopes the muzzle of the gun over the projecting head end of the fastener pin and this positions the latter for an impact blow by the piston when the gun is fired. This greatly improves the ease and speed with which the fastener pins can be driven into the mold wall because all the operator is required to do, once the panels are hung in the ingot mold, is to reload the powder cap after each shot, seek out the end of the fastening pin which projects from the heat insulation panel, telescope the gun muzzle over this pin, and operate the firing mechanism of the gun to drive the pin home into the mold wall. Preferably, in accordance with the present invention the gun is fired by means of a remote firing mechanism which the operator can actuate while standing upright on top of the mold. Also, accidental firing of the impact gun produces no safety hazard because the fastener pin is not present in the gun except when the gun is positioned to drive the pin into the mold wall.

Accordingly, it is an object of the present invention to provide a novel and improved method of installing a heat insulation panel in an ingot mold with greater speed, safety and convenience.

Another object of this invention is to provide a novel pre-assembled, unitary heat insulation panel and fastener assembly for attachment to the inside of an ingot mold.

Another object of this invention is to provide a novel and improved fastener pin assembly for use in attaching a heat insulation panel to the inside of an ingot mold.

Another object of this invention is to provide a novel and improved fastener pin for more securely attaching a heat insulation panel to the inside of an ingot mold.

Another object of this invention is'to assurethatby presetting the fastener pin in the heat insulation panel perpendicular to the face of the ingot mold the fastener pin point will penetrate the surface of the ingot mold at right angles to the face of the ingot mold, thereby elimimating hazardous fishhooking of the fastener pin with subsequent loss of holding power.

Further objects and advantages of the present invention will be apparent from the following detailed description with reference to the accompanying drawing, in which:

FIGURE 1 is a fragmentary exploded perspective view showing the heat insulation panel and one of the fastener pin assemblies therefor in accordance with a first embodiment of the present invention;

FIGURE 2 is a horizontal section through the heat insulation panel with the FIG. 1 fastener pin pre'set therein;

FIGURE 3 is a view similar to FIG. 2 and showing the heat insulation panel fastened to the inside of an ingot mold by driving the fastener pin from the pre-set phantom line position to the final full-line position;

FIGURE 4 is a perspective view showing a workman installing heat insulation panels in an ingot mold in accordance with the present invention;

FIGURE 5 is an enlarged elevational view of the pointed end of the novel fastener pin in accordance with the present invention; and

FIGURE 6 is a perspective view of a second embodiment of the fastener pin assembly in accordance with the present invention.

Referring to FIGS. 1 and 2, in accordance with a first embodiment of the present invention, before being installed in an ingot mold the usual heat insulation panel 10 is provided with preferably as many pre-assembled fastener pin assemblies 11 as are necessary for fastening it securely to the inside of the mold.

In one practical embodiment, the insulation panel 10 is predominantly silica sand with approximately equal parts of fibrous material, such as asbestos, and a suitable binder, such as a phenolic resin.

The fastener pin assembly 11 in this particular embodiment comprises a relatively broad area, flat, rectangular impact plate 12, which is held flush against the inside face 13 of the insulation panel 10 by staples 14 driven through the plate. Alternatively, the impact plate 12 may be attached to the insulation panel 10 by integral tangs on the plate which are driven into the panel, or by any other suitable attachment members which will be effective to hold the plate securely against the panel, as shown, or it may be held by the fastener pin itself, the pin being described hereinafter. Alternatively, the impact plate 12 may be molded into the panel as the panel is formed, or the impact plate may be glued to the panel.

The impact plate 12 has a central opening 15 which is surrounded by four tabs, including a pair of fiat, opposed tabs 16, 17, which are coplanar with the plate proper, and a pair of opposed, inwardly-bent tabs 18, 19. As best seen in FIG. 2, the bent-in tabs 13 and 19 are formed integral with the plate 12 and they extend into the thickness of the insulation panel 10 at opposite acute angles of approximately 20 to the plane of plate. These bent-in tabs terminate in confronting arcuate edge portions 20 and 21 which are offset inwardly from the plane of the impact plate and which partially define the plate opening 15. The tabs 16 and 17, which are coplanar with the plate proper, also terminate in confronting arcuate edges 22 and 23 (FIG. 1) which define the remainder of the outline of the plate opening 15.

The fastener pin assembly 11 also includes a fastening pin 24 having an elongated cylindrical shank 25 which carries a fiat metal washer 26. The washer 26 has a tight interference frictional fit on the fastener pin. The fastener pin has a pointed inner end 27 and an enlarged head 28 on its outer end.

,As best seen in FIG. 2,, in accordance with the preferred form of the present invention the fastener pin assembly is pro-assembled with the heat insulation panel 10 to provide a unitary structure by first attaching the impact plate 12 to the inside face 13 of the panel by the staples 14 or other methods previously suggested and then driving the pointed end of the fastener pin through the opening 15 in the plate 12 and into the panel 10 until the washer 26 abuts against the impact plate 12. Preferably this is done without disturbing the original position of the washer 26 on the fastener pin, so that this position of the washer accurately predetermines the depth of penetration of the fastener pin into the panel 10 during this preassembly. As shown in FIG. 2, the fastener pin preferably penetrates most, but not all, of the Way through the thickness of the panel 10. The cylindrical shank 25 of the fastener pin 24 is gripped frictionally by the arcuate edges 20, 21, 22 and 23 of the integral tabs 16-19 on the impact plate, so that the fastener pin cannot become dislodged from the panel 10 during its shipment to the ingot mold or while it is being handled.

Referring to FIG. 3, the heat insulation panel 16 is to be positioned against the fiat inside face 30 of an upstanding wall 31 of an ingot mold and then fastened to this wall by driving the fastener pin 24 from the pre-set phantom line position in FIG. 3, in which it projects from the panel, to the final full-line position of FIG. 3, in which it penetrates completely through the panel 10 and into the ingot mold wall 31. In this final position the fastener pin head 28 may abut against the washer 26, as shown in FIG. 3, or it may be spaced outwardly from the washer. The fastener pin is driven home by applying an impact blow on the head end of the fastener pin of sufficient force to drive the fastener pin shank through the frictionallyheld Washer 26 and through the opening 15 in the impact plate until the pointed end 27 of the fastener pin has passed completely through the remaining thickness of the heat insulation panel 10 and into the ingot mold wall 31 to the required depth which will insure secure attachment.

-The impact plate 12 distributes the shock of the impact blow over a relatively broad area of the insulation panel to avoid breaking the latter or driving the washer through the panel, which otherwise would tend to happen due to the physical characteristics of the panel 10.

The depth to which the fastener pin 24 is pre-set into the insulation panel 10 preferably is chosen so that, when the fastener pin is driven into the ingot mold wall, it will penetrate into the latter a sufficient depth to provide a secure fastening, even if there is as much as inch to /2 inch of steel scrap or slag on the ingot mold wall behind the panel.

Referring to FIG. 4, in accordance with one aspect of the present invention such attachment of the insulation panel 10 to the ingot mold is done by the remotely-operated firing of an explosive powder-actuated impact fastener tool G. As shown in this figure, the insulation panels 10 may be suspended in position against the inside of the respective walls of the ingot mold by means of wire hangers 35 which are looped over respective rigid bars 36 resting on top of the ingot mold or by other means, not shown. Each insulation panel 10 preferably has the required number of fastener assemblies 11 pre-assembled in place, as already described in detail, with the head end of each fastener pin projecting from the panel, as shown in phantom in FIG. 3.

The gun-like impact tool G preferably is of a known type having an explosive powder charge cap for operating a piston which is slidable within the barrel of the gun. The muzzle of the gun barrel has a recess for receiving the head end of the fastener pin, and when the powder charge is fired the piston inside the gun barrel drives the fastener pin completely through the insulation panel and into the mold wall. The tool G is provided with a trigger and, in accordance with the present method, a remote control firing element, including a flexible cable C, is connected to the trigger, This remote control element extends from the gun above the top of the ingot mold. The trigger of the impact tool is operated by an upward pull on the cable C, which may be done by a manuallyoperated remote control firing element, not shown. As shown in FIG. 4, the tool G is attached to the lower end of a rigid handle H. The workman holds the upper end of this handle H and operates the remote control firing element, including cable C, while standing erect on top of the mold or on an adjacent platform.

In the use of this powder-actuated piston-type impact tool, the operator, holding the handle H, telescopes the gun muzzle over the outwardly-projecting head end of the fastener pin 24 which is pre-set in the insulation panel, so that the fastener pin is now positioned to be engaged by the piston in the gun barrel. When an upward pull is exerted on the control cable C, such as by means of a remote control firing mechanism, this operates the trigger to fire the tool to drive the fastener pin into the mold wall. This may be done while the operator is standing erect on top of the mold as shown in FIG. 4, or on an adjacent platform, not shown. There is no necessity for the operator to insert the fastener pin manually into the tool before positioning the tool against the heat insulation panel, as in the prior practice, because the fastener pin is already in place in the panel 10, and between successive firings the operator need only replace the explosive charge cap in the tool. Also, the powder-actuated pistontype impact tool need not have the aforementioned retractable safety nose to prevent accidental firing of the tool. Consequently, the time between successive firings of the tool is greatly reduced and there is no safety hazard because the fastener pin is never in place in the tool except when the tool is telescoped over the fastener pin which is pre-set in the panel Referring to FIG. 5, in accordance with the preferred embodiment of the present invention the fastener pin 24 has a novel construction which more effectively prevents it from being dislodged from the mold wall 31 after it is driven in, as shown in the full-line position of FIG. 3. Referring to FIG. 5, the pointed end 27 of the fastener pin has a rounded and tapered configuration, commonly referred to as an ogive shape. This rounded and tapered end of the fastener pin has a curvature such that at its juncture with the shank 25 a distinct corner 39 is formed, as shown somewhat exaggerated in FIG. 5. This is in contrast to the prior practice of providing a smoothly merg ing or tangential blending of the ogive-shaped end of the fastener pin with the shank of the fastener pin by having the curvature of the ogive, where it is joined to the shank, such that there is no corner or other discontinuity between them, as indicated by the phantom lines 25 in FIG. 5. In other words, in the present fastener pin the tangent of the curve of the ogive tip at its intersection with the shank of the fastener pin does not extend along the shank as it would if the ogive blended into the shank of the pin, but rather at a diverging angle with respect to the shank, proceeding away from the tip.

It has been found that the provision of this corner or discontinuity 39 between the uniform diameter shank 25 and the progressively decreasing diameter ogive-shaped tip 27 of the fastener pin enables it to have an unexpectedly more secure embedding in the cast iron mold wall when driven into the latter because cast iron has low resiliency, and when displaced by the entrance of the fastener pin point, grips more securely on shank 25, particularly at the distinct corner 39, than if the cast iron were displaced still more by a tip which merges or blends smoothly with the shank, as shown at 25 in FIG. 5.

FIGURE 6 shows an alternative embodiment of the present fastener which consists of a fastener pin 24,

preferably having a pointed end identical to the fastener pin already described, and an impact plate 40. The shank of this pin is knurled at 46 just ahead of the head 28. The plate 40 is a non-rectangular parallelogram in outline, having a pair of short opposite side edges 41, 42 and a pair of longer opposite side edges 43, 44 joining them. The edges 41 and 44 extend at substantially less than 90 to one another and they form a sharp corner which may be straddled by a staple 14', shown in phantom in FIG. 6, for attaching the impact plate to the heat insulation panel. The opposite corner of this plate, at the intersection of its remaining side edges 42 and 43, may be similarly straddled by such a staple.

The impact plate 40 has a circular opening 45. This opening receives the shank of the fastener pin 24 with a tight frictional fit.

The impact plate 40 and pin 24' may be assembled together as shown in FIG. 6, with the pointed end of the fastener pin projecting past the plate 40 by an amount corresponding to the desired depth of its partial penetration through the insulation panel. The fastener pin may be driven into the insulation panel until the plate 40 abuts against the face of the panel, and then the plate is stapled to the panel to provide the pre-assembled unitary structure of the panel and the fastener assembly. The knurled surface 46 on the shank of the fastener pin will be securely gripped by the frictional fit with the impact plate 40 at the latters opening 45 to insure that the impact plate cannot come loose from the fastener pin after the latter is driven into the side of the mold.

While certain presently-preferred embodiments of the present pre-assembled panel and fastener pin structure and of the fastener pin itself, as well as the preferred method of installing this panel and fastener pin structure in an ingot mold, have been described in detail with reference to the accompanying drawing, it is to be understood that modifications which depart from these particular embodiments may be adopted without departing from the scope of the present invention, as defined in the appended claim.

Having described our invention, we claim:

1. A method of attaching a heat insulation panel to the inside of an upstanding wall of an ingot mold which comprises the steps of:

positioning against the inside of said wall a heat insulation panel having fastener pins pre-set therein with their head ends projecting from the face of the panel away from said wall;

telescoping over the head end of each pin the muzzle of an explosive-powder-actuated impact tool having a trigger for firing an explosive charge and a triggercontrol element extending away from the trigger outside of the ingot mold;

and actuating said trigger-control element outside of the ingot mold to fire the tool to drive said fastener pin into said wall of the ingot mold.

References Cited UNITED STATES PATENTS 1,616,427 2/ 1927 Isaacson 52-375 1,725,787 8/1929 Ellis 52-362 1,925,774 9/1933 Phillips 52362 2,109,448 2/1938 Welch 52-747 2,702,902 3/ 1955 Portouw et a1 2279 2,751,808 6/1956 MacDonald et a1. -30 2,761,348 9/1956 Williams et a1. 85-10 FRANCIS K. ZUGEL, Primary Examiner. 

1. A METHOD OF ATTACHING A HEAT INSULATION PANEL TO THE INSIDE OF AN UPSTANDING WALL OF AN INGOT MOLD WHICH COMPRISES THE STEPS OF: POSITIONING AGAINST THE INSIDE OF SAID WALL A HEAT INSULATION PANEL HAVING FASTENER PINS PRE-SET THEREIN WITH THEIR HEAD ENDS PROJECTING FROM THR FACE OF THE PANEL AWAY FROM SAID WALL; TELESCOPING OVER THE HEAD END OF EACH PIN THE MUZZLE OF AN EXPLOSIVE-POWDER-ACTUATED IMPACT TOOL HAVING A TRIGGER FOR FIRING AN EXPLOSIVE CHARGE AND A TRIGGERCONTROL ELEMENT EXTENDING AWAY FROM THE TRIGGER OUTSIDE OF THE INGOT MOLD; AND ACTUATING SAID TRIGGER-CONTROL ELEMENT OUTSIDE OF THE INGOT MOLD TO FIRE THE TOOL TO DRIVE SAID FASTENER PIN INTO SAID WALL OF THE INGOT MOLD. 